"Paver sand" really does help get a better installation. Paver sand is a sharp sand, meaning that under a microscope the sand is, well...sharp...instead of being rounded or soft. Sounds silly and overly simplistic, but it has an effect on the outcome of the project. It's the irregular shape of the sharp sand granules that will help the sand to bind the adjacent pavers together, that in turn will prevent eventual movement of the pavers in the finished patio. Best, Mongo

how consistent should the amount of sanding between pavers be? there are some on our newly repaved-with-pavers-lanai that look like they have almost no sand between pavers and other areas where the sand is flush to the pavers' edges... more gap areas than flush areas on the lanai edges are on either a poured footing or something that won't move like pool coping or house and are mortared down so "creeping" will be minimal but aesthetics and ability to trap moisture/dirt is increased with more gapping to my mind... the driveway done at the same time with same brand of pavers (but different color and style/pattern) has much more consistently fully sanded seams between pavers than the lanai... the lanai was laid over the original concrete patio which was not cracked/buckling so there is smooth base under the pavers... can't post photos here--don't upload to any site to link to but just want to know what the tolerance for gaps is with granite I know some people accept larger gaps in seams-- I had great granite guys that did my home remodel and seams were minimal--1/4 inch or less... had friend who had her kitchen done and she has noticeable seam that is maybe 3/8 of inch--and was told that was "good" job...

I'm sort of in the camp of no powerwashing and then re-polymeric sanding. Just as this video explains: https://www.youtube.com/watch?v=yk3hnUkMgtE In theory you have to remove all the old polymeric on the sides of every paver, down to the regular non-polymeric sand base, in order to not have new polymeric try to bond with old polymeric. By attempting this it's very likely you'll either have some of the old polymeric still in there or much worse powerwashing out some of the base sand which would create a lumpy patio. Directly blasting down with a powerwasher with an aggressive nozzle is a big no no. Maybe a surface attachment would be better or keeping a decent angle instead of pointing straight down. This is what most people do I think, they'll still go at it with a powerwasher on an angle and get a decent amount of the old polymeric out and then apply new polymeric and hope for the best bond. It'll usually last at least a couple years and I have definitely seen them leave hardened sand piles. I agree with the video and what your contractor did (tried) by using regular sand and a joint stabilizer epoxy which will bond better to the old polymeric instead of trying to blast all the old poly out. The problem just seems that your contractor didn't use enough product, watered it down or something. I would definitely be calling them based on pictures if a decent amount of patio looks like that are there's not downspout or gutter issues causing that. Maybe he didn't tamp the wider joints. Even polymeric would fill joints that wide though, it just doesn't last as long in wider joints is all. Neither joint stabilizer nor polymeric last very long though, maybe a few years, and joint stabilizer product can become expensive even if it might be a better method. On a small patio, It'll be about $250 more in materials per renovation to use joint stabilizer and plain sand instead of polymeric, and if I'm not mistaken polymeric would actually last a bit longer but there's the bonding issue of using new on top of old polymeric (plus potential of idiot with powerwasher blasting too deep if he knows to get a lot of the old out). I think this is something most people can do themselves even possibly with a regular garden hose pressure increasing attachment if that's enough to get some of the old poly out, and then just broom out some polymeric over the whole patio and tamp the wider joints with a homemade tamp of wood and carpet or rubber pad or something and add more sand after that until it's packed to the top, then leaf blower the excess sand off and mist wash the polymeric to activate it, or use joint stabilizer and sand instead of polymeric. but that's not to say you should fix this job yourself, if a decent amount looks like your pics, that's a pathetic fix and you should be calling them and make a small claims court claim if they refuse to fix it. EDIt, and yes you can also just use plain sand and no sealer but will need to do it every year probably as it washes out.

There seems to be some differences in terms. You'd be more inclined to start with a sublayer (several inches thick) of crusher run gravel (infinitely mixed sizes from 1" down to dust) in the North. Over that and in the South, we use PAVER BASE sand. It is crunchy crushed concrete with some 1/4" bits down to sharp sand and dust. It is kind of like Grape Nuts cereal. All of this so far is base and is packed down hard and tight. Next comes a 1" setting bed layer of sand that is screeded out and is left undisturbed and uncompressed. It is not watered or packed down. The pavers are carefully set on it. After all the pavers are set and the edge restraint is installed, then the whole field of pavers is tamped down in several passes with a mechanical or manual tamper. After the first tamping, sand is swept into the joints. (It can be any kind of sand that fits; masonry sand is finest so is easiest to use. I've used that, play sand, and paver base sand, too. Since the latter has 1/4" bits that won't fit into the joints, they will be swept off at the end.) More tamping. More sand. Watering. Tamping. More watering and more tamping. You are done when no more sand can fit in the joints and no more compression can be achieved.